The present invention relates to internal combustion engines having a piston and a connecting rod connected to a crank shaft by a crank pin and bearing, where the crank pin includes a hole forming part of an oil passageway for routing oil from a hole in the crank shaft to the bearing.
Coughlin U.S. Pat. No. 5,615,642 discloses an engine where an oil passageway (97) in a crank pin (38) routes oil from a crank spindle (28) to a bushing (64). (See holes 88, 90, 92, 94, and 97.) Also, see Enright U.S. Pat. No. 7,418,939, oil passage in FIG. 2. However, an improved arrangement is desired that facilitates machining and manufacture of the crank pin, and that does so without sacrificing structure and function, and without adversely affecting distribution of oil.
For example, crank pins of the type illustrated herein have an axial hole and also have an oil passageway hole that extends between its inner and outer surfaces at a location inboard from a plug that plugs the axial hole. A positioning of the plug is critical so that the plug isn't inboard so far that it accidentally closes off all or part of the oil passageway hole, and so that the plug isn't outboard so far that it extends beyond an end of the crank pin. Alignment of their oil passageway hole with mating oil passageway holes in mating components can be difficult.